Evidence for kinetic inhomogeneity in the curing of epoxy using the near-infrared multispectral imaging technique

The kinetics of curing of an epoxy resin by amine was studied using a near-infrared (NIR) multispectral imaging spectrometer. This imaging spectrometer is capable of sensitively and rapidly recording NIR spectral images of a sample because it was constructed with an acousto-optic tunable filter and an InGaAs focal plane array NIR camera. The high sensitivity and fast scanning ability of the spectrometer make it suitable for kinetic determination of fast reactions. Additionally, it has features that conventional NIR spectrometers cannot offer, namely, its ability to provide kinetic information at different positions within a sample. Furthermore, the high spatial resolution and sensitivity of the InGaAs camera make it possible to determine the kinetics from data collected by a single pixel in the camera. The kinetics of curing of epoxy by amine, determined by this multispectral imaging instrument, show that the reaction rates within the sample are very inhomogeneous. Because of this kinetic inhomogeneity, differences in the degrees of cure at different positions within the sample can be as high as 37% when data from only a single pixel were used for calculation. The inhomogeneity was not be observed if an average of a large number of pixels were used.     

Functional performance in people with chronic obstructive pulmonary disease

The extent to which individuals with a chronic physical illness perform their day-to-day activities and maintain the independence and autonomy they desire is both an indicator of adaptation and an important clinical outcome criterion. Yet the concept of functional performance is not well understood. Studies of people with chronic obstructive pulmonary disease (COPD) have attempted to identify physiologic and psychosocial factors that contribute to functioning in this population. These studies have used a melange of terms, including functional status, functional ability, quality of life, and health status interchangeably. They have also employed a variety of instruments to operationalize functional performance and an assortment of predictors to understand the phenomena. Perhaps as a result of this disarray, no attempt has been made to synthesize the literature for nursing research and practice. The purpose of this paper is to summarize the research on functional performance in people with COPD, indicate areas of understanding and quandary, suggest possible flaws, and propose several new directions for practice and research.     

Somatic antigens of pseudomonads: structure of the O-specific polysaccharide of Pseudomonas fluorescens biovar B, strain IMV 247

The O-specific polysaccharide of Pseudomonas fluorescens biovar B, strain IMV 247, was studied by acid hydrolysis, GLC-MS and 1H and 13C NMR spectroscopy, including 1D and 2D NOE, 2D hybrid TOCSY and ROESY (TORO), and 2D H-detected heteronuclear multiple-bond correlation (HMBC) experiments. The polysaccharide was found to contain L-rhamnose, 3.6-dideoxy-3-[(S)-3-hydroxybutyramido]-D-glucose (D-Qui3NHb), 2-acetamido- 2,4,6-trideoxy-4-[(S)-3-hydroxybutyramido-D-glucose (D-QuiNAc4NHb) and 2-acetamido-2- deoxy-D-galacturonic acid (D-GalNAcA). Partial acid hydrolysis of the polysaccharide resulted in a non-reducing GalNAcA-->QuiNAc4NHb disaccharide with the 3-hydroxybutyryl group glycosylated intramolecularly by the QuiN4N residue. The following structure of the tetrasaccharide repeating unit of the polysaccharide was established:-->4) -alpha-D-GalpNAcA-(1-->3)- alpha-D-QuipNAc4NHb-(1-->2)-beta-D-Quip3NHb-(1-->2)-alpha-L- Rhap(1-->.     

Stable expression of manganese superoxide dismutase (MnSOD) in insulinoma cells prevents IL-1beta- induced cytotoxicity and reduces nitric oxide production

The fact that insulin-producing islet beta-cells are susceptible to the cytotoxic effects of inflammatory cytokines represents a potential hinderance to the use of such cells for transplantation therapy of insulin-dependent diabetes mellitus (IDDM). In the current study, we show that IL-1beta induces destruction of INS-1 insulinoma cells, while having no effect on a second insulinoma cell line RIN1046-38 and its engineered derivatives, and that this difference is correlated with a higher level of expression of manganese superoxide dismutase (MnSOD) in the latter cells. Stable overexpression of MnSOD in INS-1 cells provides complete protection against IL-1beta-mediated cytotoxicity, and also results in markedly reduced killing when such cells are exposed to conditioned media from activated human or rat PBMC. Further, overexpression of MnSOD in either RIN- or INS-1-derived lines results in a sharp reduction in IL-1beta-induced nitric oxide (NO) production, a finding that correlates with reduced levels of the inducible form of nitric oxide synthase (iNOS). Treatment of INS-1 cells with L-NMMA, an inhibitor of iNOS, provides the same degree of protection against IL-1beta or supernatants from LPS-activated rat PBMC as MnSOD overexpression, supporting the idea that MnSOD protects INS-1 cells by interfering with the normal IL-1beta-mediated increase in iNOS. Because NO and its derivatives have been implicated as critical mediators of beta-cell destruction in IDDM, we conclude that well regulated insulinoma cell lines engineered for MnSOD overexpression may be an attractive alternative to isolated islets as vehicles for insulin replacement in autoimmune diabetes.     

Quality of life. Issues for persons with neuromuscular diseases

Improving quality of life has always been a goal of rehabilitation medicine. However, health care providers often do not know much about the quality of life of individuals with neuromuscular diseases, nor what factors are critical to achieving a good quality of life. Lack of knowledge about subjective quality of life factors can negatively influence expectations and selection of treatments. In the most glaring cases, a physician's subjective but incorrect assessment of a disabled individuals' quality of life may prevent life-sustaining interventions. As a group, the quality of life of individuals with NMD is not much different than nondisabled controls and is substantially better than presumed by the general public and, often times, by health care workers. Nevertheless, their quality of life is reduced in certain areas. Surprisingly, level of disability is not a critical factor that significantly alters life satisfaction. Presumably, this is because physical functioning has been adequately managed. The greatest problems that individuals with neuromuscular disease identified were: lack of information about the disease and services; poor coordination of services; negative attitudes; and a diminished expectation of their potential. In addition, people with severe disabilities had significant problems obtaining, financing, and managing personal care attendants. Factors related to a good quality of life were related to perceived control, perceived health status, but not disability. The more that people could do for themselves, either on their own or with personal care assistants, assistive devices, and use of technology, the better their quality of life.     

Aerobic exercise and normotensive adults: a meta-analysis

Using the meta-analytic approach, the purpose of this study was to examine the effects of aerobic exercise on resting systolic (SYS) and diastolic (DIA) blood pressure in normotensive adults: The results of 35 human clinical training studies published in English-language journals between 1963 and 1992 and representing 1,076 subjects (800 exercise, 276 control) met criteria for inclusion. Across all categories and designs, statistically significant post-exercise reductions were found for both SYS and DIA blood pressure (mean +/- SD, SYS: -4.4 +/- 6.6 mm Hg, 95% CI, -6.2 to -2.6 mm Hg; DIA: -3.2 +/- 3.2 mm Hg, 95% CI, -4.0 to -2.2 mm Hg). When partitioned according to type of study: 1) (randomized controlled trials (RCT), 2) controlled trials (CT), and 3) no controls (NC), the following changes were noted: RCT, SYS: -4.5 +/- 7.2 mm Hg, 95% CI, -7.1 to -1.2 mm Hg; DIA: -3.8 +/- 2.9 mm Hg, 95% CI, -5.0 to -2.6 mm Hg; CT, SYS: -2.8 +/- 6.9 mm Hg, 95% CI, -10.0 to 4.4 mm Hg; DIA: -5.0 +/- 3.7 mm Hg, 95% CI, -8.9 to -1.1 mm Hg; NC, SYS: -4.7 +/- 6.1 mm Hg, 95% CI, -7.5 to 1.9 mm Hg; DIA: -1.7 +/- 3.0 mm Hg, 95% CI, -3.2 to -0.36 mm Hg. We concluded that aerobic exercise results in small reductions in resting SYS and DIA blood pressure among normotensive adults.     

Controlled ultrasound tissue erosion

The ability of ultrasound to produce highly controlled tissue erosion was investigated. This study is motivated by the need to develop a noninvasive procedure to perforate the neonatal atrial septum as the first step in treatment of hypoplastic left heart syndrome. A total of 232 holes were generated in 40 pieces of excised porcine atrial wall by a 788 kHz single-element transducer. The effects of various parameters [e.g., pulse repetition frequency (PRF), pulse duration (PD), and gas content of liquid] on the erosion rate and energy efficiency were explored. An Isppa of 9000 W/cm2, PDs of 3, 6, 12, and 24 cycles; PRFs between 1.34 kHz and 66.7 kHz; and gas saturation of 40-55% and 79-85% were used. The results show that very short pulses delivered at certain PRFs could maximize the erosion rate and energy efficiency. We show that well-defined perforations can be precisely located in the atrial wall through the controlled ultrasound tissue erosion (CUTE) process. A preliminary in vivo experiment was conducted on a canine subject, and the atrial septum was perforated using CUTE.